package Demo2;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
import java.util.Stack;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {

        Stack<Character> stack = new Stack<>();
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        char[] chars = str.toCharArray();

        for(int i = 0; i < chars.length; i++) {

        }
    }
}